EDAC/mc_sysfs: Convert sprintf()/snprintf() to sysfs_emit()

Per Documentation/filesystems/sysfs.rst, show() should only use
sysfs_emit() or sysfs_emit_at() when formatting the value to be returned
to user space.

Generated by:

  make coccicheck M=<path/to/file> MODE=patch \
    COCCI=scripts/coccinelle/api/device_attr_show.cocci

No functional change intended.

  [ bp: Massage. ]

Signed-off-by: Li Zhijian <lizhijian@fujitsu.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20240314084628.1322006-1-lizhijian@fujitsu.com